scholarly journals High-resolution provenance of desert dust deposited on Mt. Elbrus, Caucasus in 2009–2012 using snow pit and firn core records

2013 ◽  
Vol 7 (5) ◽  
pp. 1481-1498 ◽  
Author(s):  
S. Kutuzov ◽  
M. Shahgedanova ◽  
V. Mikhalenko ◽  
P. Ginot ◽  
I. Lavrentiev ◽  
...  
Keyword(s):  
Middle East ◽  
Meteorological Data ◽  
Source Region ◽  
Anthropogenic Sources ◽  
Dust Deposition ◽  
Hysplit Model ◽  
Significant Difference ◽  
Caucasus Mountains ◽  
Modal Values ◽  
Firn Core

Abstract. The first record of dust deposition events on Mt. Elbrus, Caucasus Mountains derived from a snow pit and a shallow firn core is presented for the 2009–2012 period. A combination of isotopic analysis, SEVIRI red-green-blue composite imagery, MODIS atmospheric optical depth fields derived using the Deep Blue algorithm, air mass trajectories derived using the HYSPLIT model and analyses of meteorological data enabled identification of dust source regions with high temporal (hours) and spatial (ca. 20–100 km) resolution. Seventeen dust deposition events were detected; fourteen occurred in March–June, one in February and two in October. Four events originated in the Sahara, predominantly in northeastern Libya and eastern Algeria. Thirteen events originated in the Middle East, in the Syrian Desert and northern Mesopotamia, from a mixture of natural and anthropogenic sources. Dust transportation from Sahara was associated with vigorous Saharan depressions, strong surface winds in the source region and mid-tropospheric southwesterly flow with daily winds speeds of 20–30 m s−1 at 700 hPa level. Although these events were less frequent than those originating in the Middle East, they resulted in higher dust concentrations in snow. Dust transportation from the Middle East was associated with weaker depressions forming over the source region, high pressure centred over or extending towards the Caspian Sea and a weaker southerly or southeasterly flow towards the Caucasus Mountains with daily wind speeds of 12–18 m s−1 at 700 hPa level. Higher concentrations of nitrates and ammonium characterised dust from the Middle East deposited on Mt. Elbrus in 2009 indicating contribution of anthropogenic sources. The modal values of particle size distributions ranged between 1.98 μm and 4.16 μm. Most samples were characterised by modal values of 2.0–2.8 μm with an average of 2.6 μm and there was no significant difference between dust from the Sahara and the Middle East.

scholarly journals Desert dust deposition on Mt. Elbrus, Caucasus Mountains, Russia in 2009–2012 as recorded in snow and shallow ice core: high-resolution "provenancing", transport patterns, physical properties and soluble ionic composition

2013 ◽  
Vol 7 (2) ◽  
pp. 1621-1672
Author(s):  
S. Kutuzov ◽  
M. Shahgedanova ◽  
V. Mikhalenko ◽  
I. Lavrentiev ◽  
S. Kemp
Keyword(s):  
Middle East ◽  
Meteorological Data ◽  
Ionic Composition ◽  
Source Region ◽  
Ice Core ◽  
Anthropogenic Sources ◽  
Dust Deposition ◽  
Significant Difference ◽  
Caucasus Mountains ◽  
Modal Values

Abstract. A record of dust deposition events between 2009 and 2012 on Mt. Elbrus, Caucasus Mountains derived from a snow pit and a shallow ice core is presented for the first time for this region. A combination of isotopic analysis, SEVIRI red-green-blue composite imagery, MODIS atmospheric optical depth fields derived using the Deep Blue algorithm, air mass trajectories derived using the HYSPLIT model and analysis of meteorological data enabled identification of dust source regions with high temporal (hours) and spatial (cf. 20–100 km) resolution. Seventeen dust deposition events were detected; fourteen occurred in March–June, one in February and two in October. Four events originated in the Sahara, predominantly in north-eastern Libya and eastern Algeria. Thirteen events originated in the Middle East, in the Syrian Desert and northern Mesopotamia, from a mixture of natural and anthropogenic sources. Dust transportation from Sahara was associated with vigorous Saharan depressions, strong surface winds in the source region and mid-tropospheric south-westerly flow with daily winds speeds of 20–30 m s−1 at 700 hPa level and, although these events were less frequent, they resulted in higher dust concentrations in snow. Dust transportation from the Middle East was associated with weaker depressions forming over the source region, high pressure centered over or extending towards the Caspian Sea and a weaker southerly or south-easterly flow towards the Caucasus Mountains with daily wind speeds of 12–18 m s−1 at 700 hPa level. Higher concentrations of nitrates and ammonium characterise dust from the Middle East deposited on Mt. Elbrus in 2009 indicating contribution of anthropogenic sources. The modal values of particle size distributions ranged between 1.98 μm and 4.16 μm. Most samples were characterised by modal values of 2.0–2.8 μm with an average of 2.6 μm and there was no significant difference between dust from the Sahara and the Middle East.

scholarly journals Using the significant dust deposition event on the glaciers of Mt. Elbrus, Caucasus Mountains, Russia on 5 May 2009 to develop a method for dating and "provenancing" of desert dust events recorded in snow pack

2013 ◽  
Vol 13 (4) ◽  
pp. 1797-1808 ◽  
Author(s):  
M. Shahgedanova ◽  
S. Kutuzov ◽  
K. H. White ◽  
G. Nosenko
Keyword(s):  
Eastern Mediterranean ◽  
Meteorological Data ◽  
Source Region ◽  
Secondary Source ◽  
Snow Pack ◽  
Dust Deposition ◽  
Hysplit Model ◽  
Pressure System ◽  
Desert Dust ◽  
Caucasus Mountains

Abstract. A significant desert dust deposition event occurred on Mt. Elbrus, Caucasus Mountains, Russia on 5 May 2009, where the deposited dust later appeared as a brown layer in the snow pack. An examination of dust transportation history and analysis of chemical and physical properties of the deposited dust were used to develop a new approach for high-resolution "provenancing" of dust deposition events recorded in snow pack using multiple independent techniques. A combination of SEVIRI red-green-blue composite imagery, MODIS atmospheric optical depth fields derived using the Deep Blue algorithm, air mass trajectories derived with HYSPLIT model and analysis of meteorological data enabled identification of dust source regions with high temporal (hours) and spatial (ca. 100 km) resolution. Dust, deposited on 5 May 2009, originated in the foothills of the Djebel Akhdar in eastern Libya where dust sources were activated by the intrusion of cold air from the Mediterranean Sea and Saharan low pressure system and transported to the Caucasus along the eastern Mediterranean coast, Syria and Turkey. Particles with an average diameter below 8 μm accounted for 90% of the measured particles in the sample with a mean of 3.58 μm, median 2.48 μm. The chemical signature of this long-travelled dust was significantly different from the locally-produced dust and close to that of soils collected in a palaeolake in the source region, in concentrations of hematite. Potential addition of dust from a secondary source in northern Mesopotamia introduced uncertainty in the "provenancing" of dust from this event. Nevertheless, the approach adopted here enables other dust horizons in the snowpack to be linked to specific dust transport events recorded in remote sensing and meteorological data archives.

scholarly journals Using the significant dust deposition event on the glaciers of Mt. Elbrus, Caucasus Mountains, Russia on 5 May 2009 to develop a method for dating and provenancing of desert dust events recorded in snow pack

2012 ◽  
Vol 12 (9) ◽  
pp. 24437-24467
Author(s):  
M. Shahgedanova ◽  
S. Kutuzov ◽  
K. White ◽  
G. Nosenko
Keyword(s):  
Eastern Mediterranean ◽  
Meteorological Data ◽  
Source Region ◽  
Secondary Source ◽  
Snow Pack ◽  
Dust Deposition ◽  
Hysplit Model ◽  
Pressure System ◽  
Desert Dust ◽  
Caucasus Mountains

Abstract. A significant desert dust deposition event occurred on Mt. Elbrus, Caucasus Mountains, Russia on 5 May 2009, where the deposited dust later appeared as a brown layer in the snow pack. An examination of dust transportation history and analysis of chemical and physical properties of the deposited dust were used to develop a new approach for high-resolution provenancing of dust deposition events recorded in snow pack using multiple independent techniques. A combination of SEVIRI red-green-blue composite imagery, MODIS atmospheric optical depth fields derived using the Deep Blue algorithm, air mass trajectories derived with HYSPLIT model and analysis of meteorological data enabled identification of dust source regions with high temporal (hours) and spatial (ca. 100 km) resolution. Dust, deposited on 5 May 2009, originated in the foothills of the Djebel Akhdar in eastern Libya where dust sources were activated by the intrusion of cold air from the Mediterranean Sea and Saharan low pressure system and transported to the Caucasus along the eastern Mediterranean coast, Syria and Turkey. Particles with an average diameter below 8 μm accounted for 90% of the measured particles in the sample with a mean of 3.58 μm, median 2.48 μm and the dominant mode of 0.60 μm. The chemical signature of this long-travelled dust was significantly different from the locally-produced dust and close to that of soils collected in a palaeolake in the source region, in concentrations of hematite and oxides of aluminium, manganese, and magnesium. Potential addition of dust from a secondary source in northern Mesopotamia introduced uncertainty in the provenancing of dust from this event. Nevertheless, the approach adopted here enables other dust horizons in the snowpack to be linked to specific dust transport events recorded in remote sensing and meteorological data archives.

scholarly journals Randomised, controlled trial of erenumab for the prevention of episodic migraine in patients from Asia, the Middle East, and Latin America: The EMPOwER study

Cephalalgia ◽  
2021 ◽  
pp. 033310242110241
Author(s):  
Shuu-Jiun Wang ◽  
Artemio A Roxas ◽  
Bibiana Saravia ◽  
Byung-Kun Kim ◽  
Debashish Chowdhury ◽  
...  
Keyword(s):  
Latin America ◽  
Middle East ◽  
Primary Endpoint ◽  
Episodic Migraine ◽  
Acute Migraine ◽  
Efficacy And Safety ◽  
Medication Treatment ◽  
Significant Difference ◽  
Specific Medication ◽  
Secondary Endpoints

Objective EMPOwER, a double-blind, randomised, phase 3 study, evaluated the efficacy and safety of erenumab in adults with episodic migraine from Asia, the Middle East, and Latin America. Methods Randomised patients (N = 900) received monthly subcutaneous injections of placebo, erenumab 70 mg, or 140 mg (3:3:2) for 3 months. Primary endpoint was change from baseline in monthly migraine days at Month 3. Other endpoints included achievement of ≥50%, ≥75%, and 100% reduction in monthly migraine days, change in monthly acute migraine-specific medication treatment days, patient-reported outcomes, and safety assessment. Results At baseline, mean (standard deviation) age was 37.5 (9.9) years, 81.9% were women, and monthly migraine days was 8.2 (2.8). At Month 3, change from baseline in monthly migraine days (primary endpoint) was −3.1, −4.2, and −4.8 days for placebo, erenumab 70 mg, and erenumab 140 mg, respectively, with a statistically significant difference for erenumab versus placebo (P = 0.002 [70 mg], P < 0.001 [140 mg]). Both erenumab doses were also significantly superior to placebo on all secondary endpoints, including the proportion of patients achieving ≥50% reduction from baseline in monthly migraine days, change from baseline in monthly acute migraine-specific medication treatment days and change from baseline in the Headache Impact Test-6™ scores. The safety profile of erenumab was comparable with placebo; no new safety signals were observed. Conclusions This study of erenumab in patients with episodic migraine from Asia, the Middle East, and Latin America met all primary and secondary endpoints. A consistent numerical benefit was observed with erenumab 140 mg versus erenumab 70 mg across all efficacy endpoints. These findings extend evidence of erenumab’s efficacy and safety to patients under-represented in previous trials. ClinicalTrials.gov identifier: NCT03333109

scholarly journals Ecological Assessment of Particulate Material (PM5 and PM10) in Urban Habitats

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 559 ◽  
Author(s):  
Edina Simon ◽  
Vanda Éva Molnár ◽  
Béla Tóthmérész ◽  
Szilárd Szabó
Keyword(s):  
Gravimetric Method ◽  
Diffraction Method ◽  
Biological Indicators ◽  
Laser Diffraction ◽  
Particulate Material ◽  
Diffraction Measurement ◽  
Tree Leaves ◽  
Dust Deposition ◽  
Positive Correlation ◽  
Significant Difference

Trees are especially useful biological indicators. We tested the suitability of tree leaves (Common Lime) to assess PM5 and PM10 deposition in the three summer months of 2018 in Debrecen city, Hungary. We also tested the usefulness of the cheap and simple gravimetric method to assess the PM deposition, and compared to the expensive, but standard laser diffraction method. We found significant differences between the concentrations of PM10 deposited on tree leaves, and on dust traps. A significant difference was found in the concentration of PM5 only in July. A significant difference was also found in the concentration of PM10 among months based on leaves and dust traps. For PM5 there was a significant difference among months based on leaves deposition. We found a significant positive correlation between the PM10 concentration deposited on leaves and on dust traps. A positive correlation was found between the concentration of PM based on the gravimetric and laser diffraction measurement methods. Our findings pointed out the particulate material’s washing by rain from leaves; thus, dust deposition on the surface of leaves is limited. Our results demonstrated that trees play an important role in the mitigation of air pollution, and they are a useful indicator of PM deposition for biomonitoring studies.

scholarly journals A comparative analysis of air pollutant concentrations and inflow trajectories: a case study of selected cities in South-Eastern Poland

2018 ◽  
Vol 45 ◽  
pp. 00060 ◽  
Author(s):  
Robert Oleniacz ◽  
Tomasz Gorzelnik ◽  
Adriana Szulecka
Keyword(s):  
Meteorological Data ◽  
Road Transport ◽  
Air Pollutant ◽  
Hysplit Model ◽  
Urban Background ◽  
South Eastern ◽  
Pollutant Concentrations ◽  
High Concentrations ◽  
Air Pollutant Concentrations

The paper presents a comparison of air pollutant concentrations in three cities in South-Eastern Poland (Krakow, Tarnow and Rzeszow) using statistical analyses and backward trajectory modelling (the HYSPLIT model). The analyses were based on particulate matter (PM10), nitrogen dioxide (NO2) and sulphur dioxide (SO2) levels as well as meteorological data from year 2017. The performed analyses revealed, among others, that the PM10 and SO2 concentrations in the air depend on the season of the year, while the NO2 concentrations are seasonally independent, which is mainly associated with emissions from road transport. Air quality in the analysed cities depends on local meteorological conditions and the structure of emission sources, including the inflowing background. The most unfavourable situation regarding high concentrations of PM10 and NO2 occurs in Krakow. For all analysed urban background stations very similar low SO2 air concentrations are observed which proves the decreasing significance of emissions from coal combustion sources.

scholarly journals High-resolution inversion of methane emissions in the Southeast US using SEAC<sup>4</sup>RS aircraft observations of atmospheric methane: anthropogenic and wetland sources

2018 ◽  
Vol 18 (9) ◽  
pp. 6483-6491 ◽  
Author(s):  
Jian-Xiong Sheng ◽  
Daniel J. Jacob ◽  
Alexander J. Turner ◽  
Joannes D. Maasakkers ◽  
Melissa P. Sulprizio ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Source Region ◽  
Regional Scale ◽  
Methane Emissions ◽  
Gas Production ◽  
Anthropogenic Sources ◽  
Oil And Gas Production ◽  
Error Characterization ◽  
The Mean ◽  
Southeast Us

Abstract. We use observations of boundary layer methane from the SEAC4RS aircraft campaign over the Southeast US in August–September 2013 to estimate methane emissions in that region through an inverse analysis with up to 0.25∘×0.3125∘ (25×25 km2) resolution and with full error characterization. The Southeast US is a major source region for methane including large contributions from oil and gas production and wetlands. Our inversion uses state-of-the-art emission inventories as prior estimates, including a gridded version of the anthropogenic EPA Greenhouse Gas Inventory and the mean of the WetCHARTs ensemble for wetlands. Inversion results are independently verified by comparison with surface (NOAA∕ESRL) and column (TCCON) methane observations. Our posterior estimates for the Southeast US are 12.8±0.9 Tg a−1 for anthropogenic sources (no significant change from the gridded EPA inventory) and 9.4±0.8 Tg a−1 for wetlands (27 % decrease from the mean in the WetCHARTs ensemble). The largest source of error in the WetCHARTs wetlands ensemble is the land cover map specification of wetland areal extent. Our results support the accuracy of the EPA anthropogenic inventory on a regional scale but there are significant local discrepancies for oil and gas production fields, suggesting that emission factors are more variable than assumed in the EPA inventory.

Impact of climatic conditions on fumonisins in maize grown in Serbia

2019 ◽  
Vol 12 (2) ◽  
pp. 183-190 ◽  
Author(s):  
B. Udovicki ◽  
I. Djekic ◽  
S. Stankovic ◽  
A. Obradovic ◽  
A. Rajkovic
Keyword(s):  
Solar Radiation ◽  
Critical Parameter ◽  
Meteorological Data ◽  
Climatic Conditions ◽  
Chi Square ◽  
High Solar Radiation ◽  
Significant Difference ◽  
Chi Square Test ◽  
Low Humidity ◽  
Low Precipitation

The influence of climatic conditions on the levels of fumonisins in maize grown in Serbia was studied over eight years (2008 to 2015), investigating the possible relationship between the levels of fumonisins contamination in maize in relation to registered weather/climatic conditions. Presence of these mycotoxins in maize after harvest was evaluated based on climatic conditions within two periods: 10 days before and 10 days after 50% silking. Categories of fumonisins levels were transformed into classes. Chi-square test for association was used in analysing relationships between results of fumonisins levels and calendar years. Mann-Whitney U-test was used to compare differences between meteorological data of two subsets in years with high and low fumonisins level. There was a statistically significant association between the fumonisins levels and calendar years χ2=247.954; (P<0.05). This study identified low precipitation and low humidity combined with high solar radiation as a critical parameter combination for elevated levels of fumonisins. The statistically significant difference in relation to some of the examined parameters suggests that maize in Serbian agro-climatic conditions is more susceptible to fungal colonisation, and subsequent fumonisin production in the period of 10 days before 50% silking.

scholarly journals Isotopic composition for source identification of mercury in atmospheric fine particles

2016 ◽  
Vol 16 (18) ◽  
pp. 11773-11786 ◽  
Author(s):  
Qiang Huang ◽  
Jiubin Chen ◽  
Weilin Huang ◽  
Pingqing Fu ◽  
Benjamin Guinot ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Isotopic Composition ◽  
Coal Combustion ◽  
Fine Particles ◽  
Meteorological Data ◽  
Early Summer ◽  
Anthropogenic Sources ◽  
Photochemical Reduction ◽  
Geochemical Parameters ◽  
Mass Dependent Fractionation

Abstract. The usefulness of mercury (Hg) isotopes for tracing the sources and pathways of Hg (and its vectors) in atmospheric fine particles (PM2.5) is uncertain. Here, we measured Hg isotopic compositions in 30 potential source materials and 23 PM2.5 samples collected in four seasons from the megacity Beijing (China) and combined the seasonal variation in both mass-dependent fractionation (represented by the ratio 202Hg ∕ 198Hg, δ202Hg) and mass-independent fractionation of isotopes with odd and even mass numbers (represented by Δ199Hg and Δ200Hg, respectively) with geochemical parameters and meteorological data to identify the sources of PM2.5-Hg and possible atmospheric particulate Hg transformation. All PM2.5 samples were highly enriched in Hg and other heavy metals and displayed wide ranges of both δ202Hg (−2.18 to 0.51 ‰) and Δ199Hg (−0.53 to 0.57 ‰), as well as small positive Δ200Hg (0.02 to 0.17 ‰). The results indicated that the seasonal variation in Hg isotopic composition (and elemental concentrations) was likely derived from variable contributions from anthropogenic sources, with continuous input due to industrial activities (e.g., smelting, cement production and coal combustion) in all seasons, whereas coal combustion dominated in winter and biomass burning mainly found in autumn. The more positive Δ199Hg of PM2.5-Hg in spring and early summer was likely derived from long-range-transported Hg that had undergone extensive photochemical reduction. The study demonstrated that Hg isotopes may be potentially used for tracing the sources of particulate Hg and its vectors in the atmosphere.

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